June 1955 to June 1964
Trans-Canada Air Lines (TCA)
CF-TGR - c/n 55 - a V.724 series Viscount
Canada registered
November 1952
An order was placed by Trans-Canada Air Lines (TCA) for fifteen Type 724 aircraft at a total cost of Can$11,500,000. This was the tenth one built.
Production Aircraft No. 60 - the 60th production Type 700 series Viscount built,
was the 26th Viscount fuselage assembled at Hurn, Bournemouth, Hampshire, England,
and the 30th Viscount assembled at Hurn, Bournemouth, Hampshire, England.
Production Order No. F10/724. Sales Order No. F10/51B. Stock Order No. F04/22B.
7 November 1954
Fuselage assembly commenced Hurn Airport, Bournemouth, Hampshire, England.
10 December 1954
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Fuselage to Erecting Shop 'E' at Hurn Airport, Bournemouth, Hampshire, England.
21 March 1955
TCA issued technical instruction V-05.04-1/1 to apply the word 'Viscount' to the tail section in 8.5 inch high red letters edged in white at the first opportunity.
2 June 1955
TCA issued technical instruction V-31.02-2/5 to apply the word 'Viscount' to the inside of the passenger loading door in 4 inch high red letters edged in white at the first opportunity.
12 June 1955
First flight from Hurn Airport Airport, Bournemouth, Hampshire, England.
It was fitted with Rolls-Royce Dart RDa3 Mark 506 engines.
20 June 1955
Aircraft passed off by TCA inspectors as completed and ready for delivery.
The word 'Viscount' had not been added to the tail at this stage.
21 June 1955
Departed from Hurn Airport, Bournemouth, Hampshire, England on delivery to Trans-Canada Air Lines (TCA) with fleet number '610'.
After arriving at Prestwick Airport, Ayrshire, Scotland it stopped overnight.
22 June 1955
Departed from Prestwick Airport, Ayrshire, Scotland to Keflavik Airport, Iceland (743 nautical miles), Bluie West One (BW1) Airfield, Southern Greenland (804 nautical miles) where it stopped for five hours, Goose Bay Airport, Newfoundland & Labrador, Canada (672 nautical miles), Dorval International Airport, Montreal, Province of Quebec, Canada (810 nautical miles).
BW1 was built during WWII to assist the transfer of military aircraft from North America to Europe and was opened in January 1942.
23 June 1955
Arrived at Dorval International Airport, Montreal, Province of Quebec, Canada.
The cabin seating was installed in Canada, as the seats used by TCA were of American manufacture.
The cabin was fitted out with 40 seats which was a reduction from the original 48 seat specification and provided more leg room.
This was heavily marketed and resulted in a high load factor compared to the 18 seat Douglas DC-3 that it replaced on some routes.
29 April 1956
This was the first Viscount on the Dorval International Airport, Montreal, Province of Quebec to Vancouver International Airport, British Columbia route.
July 1956
Cabin interior changed to a two class 44 seat arrangement.
9 July 1956
Whilst operating the O'Hare Airport, Chicago, USA to Malton Airport, Toronto and Uplands Airport, Ottawa, Ontario, Canada service carrying 31 passengers and 4 crew at FL190 (19,000 feet), between the Great Lakes Michigan and Erie near the town of Flat Rock, Wayne County, Michigan, USA, there was a momentary drop in the rpm of the No. 4 engine. The engine's speed fell 200 to 300 rpm below the normal cruise figure of 13,600 and then returned to normal for about five minutes, then suddenly increased to about 14,000. Shortly afterwards, as the pilots attempted to feather the propeller, the overspeed condition increased appreciably and their efforts, using both the manual and automatic feathering systems, appeared to be in vain.
As the crew continued their attempts to feather the offending propeller, the Viscount's airspeed decreased, and so did the sound of the engine's overspeed. Increasing power on the remaining three engines countered the loss in airspeed, but the increasing whine of the No.4 engine indicated its rpm was rising again.
The Captain immediately declared an emergency to Detroit control and the Viscount was cleared to descend. Reducing power on Nos. 1, 2 and 3 engines, the crew began an emergency descent at close to the aircraft's maximum airspeed.
Although they had been cruising above a cloud layer, breaks in the clouds permitted the descent to be made visually and as the Visount descended through about 11,000 feet, the crew depressurised the cabin.
Less than a minute later, as the aircraft's altitude decreased to around 9,000 feet, the No. 4 propeller and the front section of the engines' reduction gearbox broke away from the rest of the engine, all four propeller blades then separated from the hub. Unknown to the pilots, one of the blades struck the No. 3 engine nacelle, before being flung through the forward part of the fuselage, killing one passenger instantly and injuring four others, together with one of the flight attendants.
Meanwhile the pilots were continuing the descent and, on reaching 3,000 feet, applied power again to Nos. 1, 2 and 3 engines to remain at that altitude. But as they did so, the rpm of the No. 3 engine failed to exceed 11,500 RPM and its fire warning system was triggered. Although the pilots could see no fire, they immediately carried out the engine fire drill, including feathering the propeller.
Now flying on only its port side engines, the Viscount continued towards Windsor Airport, Ontario, Canada and 10 minutes later, with the airport fire service and ambulances standing by, the pilots carried out a successful emergency landing without brakes. Not until the Viscount had rolled to a stop did they learn that a propeller blade had penetrated the fuselage with fatal results. Ambulances rushed the injured to hospital.
Examination of the aircraft at Windsor Airport revealed that the propeller and the front section of the No. 4 engine reduction gear mechanism had broken away in flight.
As the propeller blades separated from the hub, one blade had passed over the top of No. 3 engine before penetrating the forward portion of the passenger cabin and inflicting major cabin damage in the area of the two most forward rows of seats. The woman killed was the one seated with her two small children in the front row of the cabin. Miraculously, neither child was injured, although the elder suffered a degree of shock. The other injured victims were a married couple and their three year old child, a middle aged businessman, and one of the flight attendants.
The No. 4 engine, when dismantled, showed evidence of oil starvation. The engine's fuel pump, propeller control unit, and oil pump are driven by bevel gears, and investigation disclosed that the driven bevel gear had sustained a fatigue failure, completely disrupting the drive. The teeth of the high speed pinion of the propeller reduction gearing were also stripped, to the extent that the propeller became uncoupled from the engine. Discolouration from overheating could be seen on the pinion and thrust bearing.
All four separated propeller blades were found on the ground in the vicinity of Flat Rock, Wayne County, Michigan, USA. Three of the propeller blades were intact, but one blade was damaged and had a section missing from it. A small piece of propeller blade recovered from the Viscount's damaged passenger cabin was found to match the missing section of the blade.
Investigators could not determine whether the No. 4 engine's momentary drop of 200 to 300 rpm had any connection with events that followed. But the initial engine overspeed to around 14,000 rpm undoubtedly occurred after the bevel gear failure, and at this brief stage of the engine difficulty, the propeller could still have been feathered.
After the failure of the bevel gear drive however, the engine was being rotated by the windmilling propeller without pressure lubrication, and as a result, the high speed pinion progressively failed. The propeller oil transfer housing was damaged in the process, preventing feathering oil pressure from being directed to the propeller. No other reason for the propeller's failure to feather could be found. The front section of the reduction gearbox broke away from the remainder of the engine as the Annulus gearwheel failed due to the excessive propeller speed.
The pilots told investigators that the second overspeed occurred just as they were first attempting to feather the propeller. By this time however, the damage that prevented feathering had already occurred.
Continuing to windmill at high speed without adequate lubrication, the propeller became uncoupled from the engine as the teeth of the high speed pinion of the propeller reduction gearing progressively stripped. By the time the Viscount was down to about 9,000 feet, still flying close to its maximum permitted airspeed, the blade retaining structure of the windmilling propeller finally gave way and the propeller flew apart.
There was no evidence of faulty material or workmanship in the recovered components of the propeller. Rather, information from the propeller manufacturer, based on the calculated blade retention strength and tests of the propeller design, indicated that a failure of this nature could be expected in the circumstances that developed.
The problem of an uncontrolled, decoupled propeller was not mentioned in the Viscount's training or operations manuals. At this early stage of the Viscount's operational life, the problem had not been envisaged by the aircraft manufacturers.
Even so, the investigators believed that, because the sound of the overspeed decreased with reduced airspeed and increased with a rise in airspeed, the pilots should have been conscious of the need to limit the Viscount's speed during the descent. In reciprocating engined aircraft, maintaining a low airspeed to reduce the rpm of an uncontrollable propeller had been a well known basic procedure for many years. Despite this, the captain elected to make an emergency descent at high airspeed. The investigators believed the propeller would not have failed as it did if the crew had instead maintained a moderate airspeed.
The failure of the No. 3 engine to respond to the crew's power application after levelling off at the lower altitude, and the engine's subsequent fire warning, were the direct result of damage inflicted by one of the detached blades of the No. 4 propeller before the blade penetrated the fuselage.
The investigators concluded that the in-flight disintegration of the propeller and its fatal outcome were the result of excessive loads imposed upon it by the aircraft's descent at too high an airspeed, while the decoupled propeller was windmilling with its rpm uncontrolled.
Repaired and returned to service.
11 March 1957
The US Civil Aeronautics Board (CAB) issued their accident report F-111-56.
 FURTHER READING: Air Disaster by Macarthur Job
10 July 1957
TCA issued instructions that all Viscounts would be repainted in a 'White Top' livery when a suitable maintenance period became available.
19 December 1958
Scheduled to enter the Winnipeg Airport, Manitoba, Canada TCA maintenance facility for the replacement of the life expired wing lower inner spar boom at approximately 6500 landings for this component. This usually took 28 days to complete.
31 August 1960
Total time 13,065 hours and 10,266 total landings.
9 January 1963
Flown to Winnipeg Airport, Manitoba, Canada and withdrawn from service and stored.
1 June 1964
Transferred to Air Canada due to a corporate name change.
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